https://www.wizard101.com/forum/ravenwood-commons/how-do-you-cancel-a-renewal-of-a-membership-8ad6a4144cbc2872014cf2981b0a4cc6
This does not delete your Wizard101 account, it just reverts it back to the "Free" sections only. The cancellation does not take effect immediately but at the next billing cycle. This is either good news or bad news depending on if you wanted some money back. No billing cycle is prorated by cancellation.
So to get only one month's membership using a credit card, you pay for a monthly membership, then follow the instructions to end the membership, causing the first month of the membership to remain paid for and all subsequent months to be cancelled. This is also described in this forum post:
http://www.wizard101central.com/forums/showthread.php?271876-Disable-automatic-renewal-for-membership
There are also Wizard101 gift cards, which can be bought both online and at major retailers like Target, ToysRUs, and BestBuy. It is hinted that these can be used to buy memberships, but oddly the dollar amounts don't quite line up because monthly membership is in increments of $9.99 and the cards are whole $10 or $20 amounts. I guess somebody is profiting from the difference.
https://www.wizard101.com/game/prepaid-card
